1. Field of the Invention
The present invention relates to a single-reel type tape cartridge having a floating-lock structure for restricting upward movement of a tape reel in nonuse status and relates to a tape drive therefor.
2. Description of the Related Art
A rotation lock structure for restricting rotation of a tape reel in nonuse status is publicly known as Japanese unexamined patent application publication No. 2004-46993 (Patent Document 1, e.g., paragraph No. 0014, FIG. 1), for instance. The rotation lock structure is composed of a locking member that is guided and supported by an upper casing so as to be movable only in vertical directions, a spring for pressing down and biasing the locking member, gear teeth provided on the locking member, gear teeth formed on inner bottom of a reel hub and corresponding to the gear teeth on the locking member, and the like. In the nonuse status, the tape reel is held, so as to be incapable of rotating, by engagement between the locking member and the inner bottom wall of the reel hub through the gear teeth on both sides. In use, the locking member can be held in an unlocked posture by upward press against the locking member by an unlock pin provided on a drive shaft of the tape drive.
In such a rotation lock structure of this type, the tape reel in nonuse status can be held so as to be incapable of rotating but cannot be restricted in upward movement thereof. Upon reception of a large external force such as drop impact, accordingly, an upper flange of the tape reel may collide with an inner wall of a main body case, thereby may deform and damage edges of a recording tape. There is a trend for thicknesses of recording tapes to decrease with advancement in recording capacity of tape cartridges, and low physical strengths of recording tapes make a cause of susceptibility of tape edges to damage.
Other than such a rotation lock structure as described above, a tape cartridge having a floating-lock structure for restricting upward movement of a tape reel is publicly known as Japanese unexamined patent application publication No. 2005-276413 (Patent Document 2, e.g., paragraph No. 0055, FIG. 2), for instance. On an inner surface of an upper wall of a main body case are provided three lock pieces that reciprocate and slide in radial directions, and upward movement of the tape reel is restricted by insert engagement of outer ends of the lock pieces between an opening edge of a reel hub and the upper wall of the case. The lock pieces are locked and biased by springs, and upward thrust at a locking member described above with an unlock pin on the tape drive unlocks the lock pieces against biasing forces of the springs. For that operation, a cam piece is integrally provided on a lower surface at inner end of the lock piece, and a release projection for unlocking the lock piece through the cam piece is provided on upper surface side of the locking member.